• Skip to main content
  • Skip to primary sidebar

Homemade Circuit Projects

Get free circuit help 24/7

Circuits for Beginners | Basic Circuits | LED Driver | Hobby Circuits | Transistor Circuits

New-Projects | Privacy Policy | About us | Contact | Disclaimer | Copyright | Videos

You are here: Home / Home Electrical Circuits / Two Tone Door bell Circuit

Two Tone Door bell Circuit

Last Updated on May 26, 2021 by Swagatam Leave a Comment

ask questions through comments

The electronic 2 tone door bell circuit is designed around the popular IC 555. The IC 555 is extensively applied in numerous varieties of timers and also as a basic oscillator circuit. In this particular project both the timer and the oscillator functions of the IC are utilized.

As soon as the indicated push-button is pushed with our finger, the IC 555 begins oscillating with a specific frequency (tone), and as soon as the push-button is released, the frequency changes, modifying the sound of the tone, and the IC now continues generating this second tone for a specific amount of time period, as determined by the RC time constant of the IC.

Hence, when the bell button is pressed once, we get a two-tone doorbell sound from the speaker which is directly attached to the IC pin#3, and operated directly by the IC 555 output.

How the Circuit Works

Referring to the diagram below, the working of this two tone doorbell circuit can be understood with the help of the following points:

The capacitor C2 gets charged at the start, and the charge reaches the supply level of +9V through resistors R2, R3 and R4.

However, because the upper end of the capacitor is linked with both pin#2 and pin#6 of the IC, therefore, as soon as the voltage across the capacitor tends to reach 6V level, the two internal comparators of the IC gets above their threshold level, causing the IC 555 at pin#3 to go low, which in turn results in the internal transistor of the IC to switch on. The action short circuits the pin#7 of the IC to ground.

But, since pin#7 is hooked up with the junction of the resistors R3 and R4 and C2, now begins getting discharged by means of the resistor R4.

During this process as soon as the voltage stored inside C2 tends to drop below 3 V, causes the output of the IC to yet again go high, switching OFF the internal transistor of the IC. This in turn immediately causes C2 to start charging again by means of the resistor R2, R3 and R4.

This sequence of action goes on repeating continuously, which causes the generation of triangular waveform across C2, creating a train of pulses at the IC output pin#3.

This train of pulses coming out from the pin#3 of the IC can be seen configured with a loudspeaker by means of the capacitor C3.

The C3 capacitor ensures that the dc component present in the pin#3 output voltage does not reach the loudspeaker and thus prevents the loudspeaker from burning.

The capacitor C2 generates the triangular waveform as it charges through 3 V to 6 V and while discharging from 6V to 3V.

If you desire to change the pitch tone of the two tone door bell circuit, to a different tone you just have to tweak the values of the resistors R2, R3, R4 or simply the change the value of C2 appropriately until the desired tone output is achieved.

Parts List

get free help for circuit diagrams

You'll also like:

  • 1.  Simple Intercom Network Circuit
  • 2.  Subwoofer Music Level Indicator Circuit
  • 3.  BLDC Ceiling Fan Circuit for Power Saving
  • 4.  Mains AC Overload protection Circuit for Voltage Stabilizers
  • 5.  Make a Simple Machine Gun Sound Effect Generator Circuit
  • 6.  Playing a Melody Using the Tone() function in Arduino

About Swagatam

I am an electronic engineer (dipIETE ), hobbyist, inventor, schematic/PCB designer, manufacturer. I am also the founder of the website: https://www.homemade-circuits.com/, where I love sharing my innovative circuit ideas and tutorials.
If you have any circuit related query, you may interact through comments, I'll be most happy to help!

Subscribe for the Latest Posts


 

Reader Interactions

Have Questions? Please post your comments below for quick replies! Comments should be related to the above artcile Cancel reply

Your email address will not be published. Required fields are marked *

Primary Sidebar



Categories

  • 3-Phase Power (15)
  • 324 IC Circuits (19)
  • 4017 IC Circuits (52)
  • 4060 IC Circuits (25)
  • 555 IC Circuits (98)
  • 741 IC Circuits (19)
  • Amplifiers (59)
  • Arduino Engineering Projects (83)
  • Audio Projects (94)
  • Battery Chargers (83)
  • Car and Motorcycle (94)
  • Datasheets (46)
  • Decorative Lighting (Diwali, Christmas) (32)
  • DIY LED Projects (89)
  • Electronic Components (97)
  • Electronic Devices and Circuit Theory (35)
  • Electronics Tutorial (109)
  • Fish Aquarium (5)
  • Free Energy (34)
  • Fun Projects (12)
  • GSM Projects (9)
  • Health Related (19)
  • Heater Controllers (28)
  • Home Electrical Circuits (100)
  • How to Articles (20)
  • Incubator Related (6)
  • Industrial Electronics (28)
  • Infrared (IR) (40)
  • Inverter Circuits (98)
  • Laser Projects (12)
  • LM317/LM338 (21)
  • LM3915 IC (25)
  • Meters and Testers (64)
  • Mini Projects (156)
  • Motor Controller (66)
  • MPPT (7)
  • Oscillator Circuits (24)
  • PIR (Passive Infrared) (8)
  • Power Electronics (33)
  • Power Supply Circuits (74)
  • Radio Circuits (9)
  • Remote Control (47)
  • Security and Alarm (61)
  • Sensors and Detectors (118)
  • SG3525 IC (5)
  • Simple Circuits (74)
  • SMPS (29)
  • Solar Controllers (60)
  • Timer and Delay Relay (53)
  • TL494 IC (5)
  • Transformerless Power Supply (8)
  • Transmitter Circuits (40)
  • Ultrasonic Projects (14)
  • Water Level Controller (45)


Circuit Calculators

  • AWG to Millimeter Converter
  • Battery Back up Time Calculator
  • Capacitance Reactance Calculator
  • IC 555 Astable Calculator
  • IC 555 Monostable Calculator
  • Inductance Calculator
  • LC Resonance Calculator
  • LM317, LM338, LM396 Calculator
  • Ohm’s Law Calculator
  • Phase Angle Phase Shift Calculator
  • Power Factor (PF) Calculator
  • Reactance Calculator
  • Small Signal Transistor(BJT) and Diode Quick Datasheet
  • Transistor Astable Calculator
  • Transistor base Resistor Calculator
  • Voltage Divider Calculator
  • Wire Current Calculator
  • Zener Diode Calculator


You can also Chat with me here:

Facebook
Twitter
YouTube
Instagram
My Facebook-Page
Quora



© 2022 · Swagatam Innovations

We use cookies on our website to give you the best experience.
Cookie settingsAccept All
Privacy & Cookies Policy

Privacy Overview

This website uses cookies to improve your experience while you navigate through the website. Please visit the Privacy Policy Page for more info.
Necessary
Always Enabled
Necessary cookies are absolutely essential for the website to function properly. This category only includes cookies that ensures basic functionalities and security features of the website. These cookies do not store any personal information.
Non-necessary
Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. It is mandatory to procure user consent prior to running these cookies on your website.
SAVE & ACCEPT